Respiratory syncytial virus (RSV) is a major cause of lower respiratory infections in immunocompetent infants and young children, as well as in immunocompromised adults and children. The rapid identification of RSV in respiratory specimens is critical for the optimal care of patients with cancer and AIDS. A rapid EIA test (TestPack RSV, Abbott Labs, N. Chicago, IL) is available for the detection of RSV antigen in nasopharyngeal aspirates, washes, and swabs. This test is currently being evaluated in parallel with direct fluorescent monoclonal antibody staining and/or shell vial culture, both more time consuming, for the ability to detect RSV not only in nasopharyngeal washes but also in bronchoalveolar lavages and/or induced sputa, two specimen types commonly received in the clinical laboratory as a means to diagnose Pneumocystis carinii infection in these patients.